The speedometer on my 2004 Mini Copper vibrates for few seconds in the reverse direction from idle position on cold start up. Problem is only seen during the initial start up of the engine. the problem disappears once the engine has warmed up and you try stop and start engine.

Thanks

Chetan

 

I think that's because your car wants to recalibrate the zero position.

 

It is your ecu resetting. Maybe a weak battery?

 

Replace the battery the problem will go away

 

That is what caused my speedometer to vibrate on start up

 

Interesting! So is this an early indication of battery going bad? Or does the ECO needs resetting and if so what is the correct procedure to reset ECO.

Thanks.

Chetan

 

there isn't really a wrong or right way to reset the ecu. Replace the battery and the ecu will reset itself. just did that on my 03.

 

Thanks! Will replace battery and see if see if it fixes my problem with vibrating speedometer.

 

From MINI2.com FAQ:

Short Answer:
It's re-zeroing itself. It only needs to re-zero after a reset, and this happens either a) when you remove the battery, or b) if you turn the ignition to position 2 more than a minute and a half after ignition off.

Long Answer:
The mechanical backstop for the stepper motor that drives the speedo needle is a few degrees below the visible zero mark on the display. Before the instrument packs leave the factory, the needles are optically aligned with the zero mark, and the difference in angle between the backstop and the zero mark is written into the memory of the instrument pack. On a reset, the needle is driven backwards into the backstop, and then forwards by the calibrated angle to the zero mark. The needle will shake as long as the motor is driving back against the backstop. Because the calibration varies between cars, the amount of time (and severity) of the shaking will also vary, and some cars audibly rattle.

Short conclusion to the long answer: It's a quirk, but go ahead and complain if you think it's really bad.